Integrated circuit devices can be adapted to detect biological markers. One such adaptation is the inclusion of bioFETs (biologically sensitive field effect transistors). As the term is used herein, a bioFET is a transistor that can be switched by being placed in contact with a liquid having a suitable composition. A suitable composition can include the presence of certain suspended solids, such as particular types of cells or biomolecules. The portion of the transistor configured to interface with the liquid is referred to as a fluid gate. A bioFET can be a dual gate transistor that includes a conventional gate, such as a gate having a polysilicon electrode. The conventional gate can be located on an opposite side of the transistor channel from the fluid gate. In such a configuration, the conventional gate can be used to modulate the effect that charge on the fluid gate has on the conductivity of the transistor channel.